Kesari and Anjana had in total 6 sons out of which Lord Hanuman was the eldest one. The names of other sons of King Kesari were: 

 1. Matimaan
 2. Shrutimaan
 3. Ketumaan
 4. Gatimaan
 5. Dhritimaan

Also, unlike Lord Hanuman, these all were married and had kids. All this is mentioned under Brahamand Purana. Apart from other things, this purana also contains the details of the family tree of Kesari and about other things in the life of Lord Hanuman. 

The source of this information are following links: 

 - [Link 1][1]
 - [Link 2][2]

Also, link of Brahmand Purana can be found in this [answer][3]


  [1]: http://hindi.speakingtree.in/slideshow/hanumanji-ke-paanch-bhai-bhi-the/%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%BE%E0%A4%82%E0%A4%A1%E0%A4%AA%E0%A5%81%E0%A4%B0%E0%A4%BE%E0%A4%A3-%E0%A4%95%E0%A5%87-%E0%A4%85%E0%A4%A8%E0%A5%81%E0%A4%B8%E0%A4%BE%E0%A4%B0
  [2]: http://hindi.speakingtree.in/slideshow/hanumanji-ke-paanch-bhai-bhi-the/%E0%A4%B8%E0%A4%AC%E0%A4%B8%E0%A5%87-%E0%A4%AC%E0%A4%A1%E0%A4%BC%E0%A5%87-%E0%A4%A5%E0%A5%87-%E0%A4%AC%E0%A4%9C%E0%A4%B0%E0%A4%82%E0%A4%97%E0%A4%AC%E0%A4%B2%E0%A5%80
  [3]: http://hinduism.stackexchange.com/a/6751/1018